Add simple scene graph

Ghost.Engine/Core/Scene.cs

@@ -2,25 +2,67 @@ using Ghost.Entities;
 
 namespace Ghost.Engine.Core;
 
-public partial class Scene
+/// <summary>
+/// Represents a lightweight handle to a loaded scene.
+/// </summary>
+/// <remarks>
+/// A Scene is a collection of entities tagged with a unique SceneID component.
+/// The Scene class provides a convenient handle to interact with all entities
+/// belonging to a particular scene within a World.
+/// </remarks>
+public sealed class Scene : IDisposable, IEquatable<Scene>
 {
     private static short s_nextSceneID = 0;
-}
 
-public partial class Scene : IDisposable
-{
     private readonly World _world;
     private readonly short _id;
-
+    private readonly string _name;
     private bool _isDisposed;
 
+    /// <summary>
+    /// Gets the world this scene belongs to.
+    /// </summary>
     public World World => _world;
+
+    /// <summary>
+    /// Gets the unique identifier for this scene.
+    /// </summary>
     public short ID => _id;
 
-    public Scene(World world)
+    /// <summary>
+    /// Gets the name of this scene.
+    /// </summary>
+    public string Name => _name;
+
+    /// <summary>
+    /// Creates a new scene handle.
+    /// </summary>
+    /// <param name="world">The world this scene belongs to.</param>
+    /// <param name="name">The name of the scene.</param>
+    internal Scene(World world, string name)
     {
         _world = world;
         _id = s_nextSceneID++;
+        _name = name;
+    }
+
+    /// <summary>
+    /// Creates a new scene handle with a specific ID.
+    /// </summary>
+    /// <param name="world">The world this scene belongs to.</param>
+    /// <param name="id">The scene ID.</param>
+    /// <param name="name">The name of the scene.</param>
+    internal Scene(World world, short id, string name)
+    {
+        _world = world;
+        _id = id;
+        _name = name;
+
+        // Update next ID if necessary
+        if (id >= s_nextSceneID)
+        {
+            s_nextSceneID = (short)(id + 1);
+        }
     }
 
     ~Scene()
@@ -28,6 +70,50 @@ public partial class Scene : IDisposable
         Dispose();
     }
 
+    public bool Equals(Scene? other)
+    {
+        if (other is null)
+        {
+            return false;
+        }
+
+        if (ReferenceEquals(this, other))
+        {
+            return true;
+        }
+
+        return _world.Equals(other._world) && _id == other._id;
+    }
+
+    public override bool Equals(object? obj)
+    {
+        return obj is Scene other && Equals(other);
+    }
+
+    public override int GetHashCode()
+    {
+        return HashCode.Combine(_world, _id);
+    }
+
+    public override string ToString()
+    {
+        return $"Scene: {_name} (ID: {_id})";
+    }
+
+    public static bool operator ==(Scene? left, Scene? right)
+    {
+        if (left is null)
+        {
+            return right is null;
+        }
+        return left.Equals(right);
+    }
+
+    public static bool operator !=(Scene? left, Scene? right)
+    {
+        return !(left == right);
+    }
+
     public void Dispose()
     {
         if (_isDisposed)